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Pruning Clematis |
By Rebecca Fitzpatrick, Colorado Master Gardener, Colorado State University Cooperative Extension, Denver County
Clematis can be a confusing group of plants to prune, since they are not all pruned the same way.
Clematis generally fall into three different categories, based on bloom time. The
earliest flowering clematis bloom on old wood, and later blooming varieties must produce
new growth in order for flower buds to form. If you are planting brand new clematis in
your garden, wait until the second growing season before undertaking any pruning.
Early flowering clematis
Early flowering clematis typically bloom in April and May, from buds produced during the
last growing season. Prune these plants immediately after blooming, but no later than the
end of July in order to give the plant enough time to produce new buds for next year.
Start by removing shoots that have bloomed. If you like, prune out select vines to control
size or shape but avoid cutting far into the main woody trunks. This group includes C.
alpina, C. macropetala, C. armandii, C. montana, and C. chrysocoma.
Large-flowered clematis
Large flowered hybrids like ‘Nelly Moser,’ ‘Miss Bateman,’
Lasurstern,’ and ‘Duchess of Edinburgh’ bloom in mid-June on stems from the
previous season and often will bloom again in late summer on new growth, though these
blooms tend to be smaller. Remove dead or weak stems in late winter or early spring,
leaving the best of last year’s buds. Once they finish blooming, deadhead all bloom
stems or cut the plant back to 12-18” to force new growth for a second round of
flowers.
Late flowering clematis
This group’s flowers are produced on the current season’s growth and are the
easiest to prune. Some types begin blooming as early as June and continue into the fall.
In early spring, cut the plant back to 24-36” since no old wood needs to be
maintained. Varieties like C. x jackmanii, C. viticella, C. flammula,
‘Royal Velours,’ and ‘Duchess of Albany’ fall into this
category.
Photograph by Judy Sedbrook.
